Journal articles on the topic 'Users-Receivers'
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1
Alemany, Jose, Elena Del Val, and Ana María García-Fornes. "“Who should I grant access to my post?”: Identifying the most suitable privacy decisions on online social networks." Internet Research 31, no. 4 (January 8, 2021): 1290–317. http://dx.doi.org/10.1108/intr-03-2020-0128.
Abstract:
PurposeOnline social networks (OSNs) provide users with mechanisms such as social circles and individual selection to define the audiences (i.e., privacy policy) of the shared information. This privacy decision-making process is a hard and tedious task for users because they have to assess the cost-benefit in a complex environment. Moreover, little is known about how users assess the cost-benefit of matching the elements of online communication and their interests. Therefore, the purpose of this paper is to develop and test a research model to understand the impact that the types of receivers and the sensitivity of messages have on privacy decisions.Design/methodology/approachA study was conducted to understand how users evaluate the cost-benefit of the disclosure action in online social networks for the different types of receivers identified and the sensitivity of the message. Data from 400 respondents was collected and analyzed using partial least squares modeling.FindingsThe findings of this study demonstrated a trade-off variance between the perceived cost-benefit and the disclosure of sensitive information with different receiver types. Disclosing personal information with trusted receivers, influencer receivers and receivers from the circle of coworkers had a positive significant effect on social capital building. Conversely, disclosing personal information with receivers from the circle of family or unknown receivers had a significant negative effect on social capital building and even a significant positive effect on privacy concerns.Originality/valueRecent literature has documented the increasing interest of the research community in understanding users' concerns and interests in making the most suitable privacy decisions. However, most researchers have worked on understanding the disclosure action from a user-centered perspective and have not considered all of the elements of online communication. This study puts the focus on all of the elements of communication during disclosure actions, taking into account the properties of the message and receivers and the impact on users' cost benefit value.
2
Pavlovčič-Prešeren, Polona, Franc Dimc, and Matej Bažec. "A Comparative Analysis of the Response of GNSS Receivers under Vertical and Horizontal L1/E1 Chirp Jamming." Sensors 21, no. 4 (February 19, 2021): 1446. http://dx.doi.org/10.3390/s21041446.
Abstract:
Jamming is becoming a serious threat to various users of global navigation satellite systems (GNSS). Therefore, live monitoring tests are required to estimate the sensitivity range of GNSS receivers under jamming. This study analyses the response of some mass-market and professional-grade receivers to intentional interferences based on different 3D jammer positions. First, the vertical jamming was investigated, followed by a horizontal experiment where the receivers were placed at three locations while the jammer was moving within a triangular area. The aim was to determine a fingerprint of the influence of the L1/E1 chirp jammer on receivers used in the research. The results show that low-cost receivers are much more susceptible to interference, while the latest generation of GNSS geodetic receivers are much more resilient. It is encouraging that positioning in the presence of jamming could be achieved on a larger scale, especially by using professional receivers. An attempt to position the jammer will be left for trials when a more frequency stable device is applied.
3
Hirsch, Christian, Benedikt Jahnel, Paul Keeler, and Robert I. A. Patterson. "Large deviation principles for connectable receivers in wireless networks." Advances in Applied Probability 48, no. 4 (December 2016): 1061–94. http://dx.doi.org/10.1017/apr.2016.65.
Abstract:
AbstractWe study large deviation principles for a model of wireless networks consisting of Poisson point processes of transmitters and receivers. To each transmitter we associate a family of connectable receivers whose signal-to-interference-and-noise ratio is larger than a certain connectivity threshold. First, we show a large deviation principle for the empirical measure of connectable receivers associated with transmitters in large boxes. Second, making use of the observation that the receivers connectable to the origin form a Cox point process, we derive a large deviation principle for the rescaled process of these receivers as the connection threshold tends to 0. Finally, we show how these results can be used to develop importance sampling algorithms that substantially reduce the variance for the estimation of probabilities of certain rare events such as users being unable to connect.
4
Januszewski, Jacek. "GNSS Receivers, Theirs Features, User Environment And Applications." Annual of Navigation 21, no. 1 (June 1, 2014): 49–58. http://dx.doi.org/10.1515/aon-2015-0004.
Abstract:
AbstractSince many years the coordinates of the position can be obtained with the use of satellite navigation and augmentation systems, SNS and SBAS, respectively. All these systems are called GNSS (Global Navigation Satellite Systems). The main task of the user segment is to transform the products delivered by the GNSS infrastructure into services that users are mainly interested in. That's why GNSS receiver selection depends on user application. Nowadays several hundred different receivers provided by more than one hundred manufacturers are available on the world market. The review of the performance parameters of GNSS receivers accessible in 2014 and last three years is presented in this paper. Additionally the paper gives the reply to some important questions as: for how many applications the given model is destined, which is the percentage of the receivers designed for marine and navigation users, which equipment features of the receiver are the most important for given application, which satellite signals apart from GPS signals can be tracked in the receiver?
5
Yoshida, Masakazu, Ayumu Nakayama, and Jun Cheng. "Distinguishability and Disturbance in the Quantum Key Distribution Protocol Using the Mean Multi-Kings’ Problem." Entropy 22, no. 11 (November 11, 2020): 1275. http://dx.doi.org/10.3390/e22111275.
Abstract:
We introduce a quantum key distribution protocol using mean multi-kings’ problem. Using this protocol, a sender can share a bit sequence as a secret key with receivers. We consider a relation between information gain by an eavesdropper and disturbance contained in legitimate users’ information. In BB84 protocol, such relation is known as the so-called information disturbance theorem. We focus on a setting that the sender and two receivers try to share bit sequences and the eavesdropper tries to extract information by interacting legitimate users’ systems and an ancilla system. We derive trade-off inequalities between distinguishability of quantum states corresponding to the bit sequence for the eavesdropper and error probability of the bit sequence shared with the legitimate users. Our inequalities show that eavesdropper’s extracting information regarding the secret keys inevitably induces disturbing the states and increasing the error probability.
6
ARGÜELLO, FRANCISCO, MANUEL BUGALLO, and MARGARITA AMOR. "MULTI-USER RECEIVERS FOR SPREAD SPECTRUM COMMUNICATIONS BASED ON CHAOTIC SEQUENCES." International Journal of Bifurcation and Chaos 12, no. 04 (April 2002): 847–53. http://dx.doi.org/10.1142/s0218127402004723.
Abstract:
Spread spectrum based on chaotic sequences is an alternative to spread spectrum based on pseudo-noise sequences. In this letter we present the application of two multi-user detection methods (parallel and successive interference cancellation schemes) to this type of code division multiple access. We demonstrate that, also for chaotic sequence-based communications, multi-user receivers significantly improve the BER with respect to single-user receivers, and that their use is practically essential with a high number of users.
7
Gabino-Campos, María Auxiliadora. "Children and young people as virtual and interactive users and receivers." Comunicar 11, no. 22 (March 1, 2004): 121–25. http://dx.doi.org/10.3916/c22-2004-18.
Abstract:
The speed in messages transmission and in the accesibility to the Internet and other technological advances have increased users and receivers intervention in mass media and have given us another way of interpersonal communication, the virtual one. This p La velocidad en la transmisión de mensajes y la accesibilidad a Internet y a los nuevos avances tecnológicos, como los sufridos en la telefonía, han incrementado la intervención de los usuarios o receptores en los medios de comunicación de masas y han proporcionado otra forma de comunicación interpersonal, la virtual. Este trabajo trata de dilucidar cómo los niños y jóvenes, una audiencia inmadura y acrítica, dotada de un elevado grado de influenciabilidad, han integrado estos avances técnicos en sus vidas y los han adoptado para satisfacer sus necesidades básicas de comunicación y de relación.
8
Popescu, Dimitrie. "Interference suppressing OFDM UWB system with multiple users and MMSE receivers." IEEE Communications Letters 11, no. 12 (December 2007): 925–27. http://dx.doi.org/10.1109/lcomm.2007.071374.
9
Farah, Ashraf. "Variation of Static-PPP Positioning Accuracy Using GPS-Single Frequency Observations (Aswan, Egypt)." Artificial Satellites 52, no. 2 (June 1, 2017): 19–26. http://dx.doi.org/10.1515/arsa-2017-0003.
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Abstract Precise Point Positioning (PPP) is a technique used for position computation with a high accuracy using only one GNSS receiver. It depends on highly accurate satellite position and clock data rather than broadcast ephemeries. PPP precision varies based on positioning technique (static or kinematic), observations type (single or dual frequency) and the duration of collected observations. PPP-(dual frequency receivers) offers comparable accuracy to differential GPS. PPP-single frequency receivers has many applications such as infrastructure, hydrography and precision agriculture. PPP using low cost GPS single-frequency receivers is an area of great interest for millions of users in developing countries such as Egypt. This research presents a study for the variability of single frequency static GPS-PPP precision based on different observation durations.
10
Argüello, Francisco, Manuel Bugallo, and Juan López. "Blind Multiuser Receivers for Chaos Based Communications." International Journal of Bifurcation and Chaos 13, no. 08 (August 2003): 2353–59. http://dx.doi.org/10.1142/s0218127403008028.
Abstract:
Recently, there has been a good deal of interest in the use of chaotic signals for direct sequence code division multiple access (DS-CDMA) communication systems. The capacity of DS-CDMA systems is interference-limited, and can therefore be increased by techniques that suppress interference. This letter is devoted to the evaluation of the impact of blind multiuser detection techniques on chaos based DS-CDMA systems. Blind receivers can suppress multiple access interference and do not require knowledge of the code sequences and propagation channels of the interference. We demonstrate that, for chaotic sequence-based communications, blind multiuser receivers significantly improve the BER with respect to single-user receivers, and that their use is practically essential with a high number of users.
11
Li, Ching, Chia-Wen Lee, Tzu-Chun Huang, and Wei-Shiang Lai. "Perspectives of Platform Operators, Content Producers, and Information Receivers toward Health and Fitness Apps." Information 11, no. 10 (October 14, 2020): 481. http://dx.doi.org/10.3390/info11100481.
Abstract:
The interactive mechanism among platform operators, content producers, and information receivers is increasingly complex in human–computer symbiosis. The purpose of this study is to identify the interactive value among platform operators, content producers, and information receivers with regard to information through the health and fitness apps by adopting an advanced Analytic Hierarchy Process (AHP) method derived from professional perspectives of app users and operators, key opinion leaders, scholars, and officers. The AHP method was allocated weightings to the evaluation criteria from the twelve panelists from three groups of platform operators, content producers, and information receivers. After focus group interviews were conducted, four dimensions and twelve sub-dimensions of the initial health and fitness apps were obtained as follows: Content category: Monitoring, exercise, journaling, and sleeping; (2) User reviews: Fuctionality, interactivity, and criticism; (3) Content updates: New feature, correctness, and new language; (4) Platform terms: Privacy, accuracy, ownership, and right of use. The study integrated the panelists’ opinions toward health and fitness apps and analyzed the weight of each indicator according to their importance by Power Choice V2.5. The results revealed that the weights of dimensions of health and fitness apps were sorted by content category, user review, platform terms, and content update, as well as that the weights of the top six sub-dimensions were followed: monitoring, exercise, functionality, interactivity, privacy, and accuracy. Content producers suggested increasing the popularity of their products by adding new features, whereas information receivers preferred to correct problems. Content producers and information receivers graded platform terms as less essential, whereas platform operators rated platform terms higher. This study can contribute to assisting the health and fitness industry and the overall strategic operative process by identifying how the effectiveness in the procedures, estimative process, and cost-down can enhance competitiveness to further improve users experience and satisfaction.
12
Covaciu, Dinu, Ion Preda, Dragoş Sorin Dima, and Anghel Chiru. "Study on the Possibility to Estimate the Vehicle Side Slip Using Two Independent GPS Receivers." Applied Mechanics and Materials 822 (January 2016): 321–30. http://dx.doi.org/10.4028/www.scientific.net/amm.822.321.
Abstract:
Slip angle is the difference between the direction a vehicle is travelling and the longitudinal plane of the vehicle body. Knowing vehicle sideslip angle accurately is critical for active safety systems such as Electronic Stability Program (ESP). Vehicle sideslip angle can be measured using optical speed sensors, inertial sensors and/or dual-antenna GPS receivers. These systems are expensive and their use is limited for many users. The goal of this paper is to analyze the possibility to estimate the vehicle sideslip angle, in real-time, by using two low-cost single-antenna GPS receivers.
13
Regis, Carlos D. M., Raissa B. Rocha, Mylene C. Q. Farias, and Marcelo S. Alencar. "Objective and Subjective Evaluation of Spatially Transcoded Videos for Mobile Receivers." Journal of Communications Software and Systems 6, no. 2 (June 21, 2010): 49. http://dx.doi.org/10.24138/jcomss.v6i2.189.
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Digital television produces video signals with different bit rates, encoding formats, and spatial resolutions. To deliver video to users with different receivers, the content needs to be dynamically adapted. Transcoding devices convert video from one format into another. The reception of digital videos using mobile receivers, implies that the spatial resolution of the video must be adjusted to fit the small display. This paper presents subjective and objective quality analysis of spatially transcoded videos. Transcoding algorithms that downsample the video frames using the moving average, median, mode, weighted average and sigma filters are considered.
14
Sodagari, Shabnam, Hamid Jafarkhani, and Homayoun Yousefi'zadeh. "Improved Cognitive Radio Receivers Using Timing Mismatch of Primary and Secondary Users." IEEE Transactions on Circuits and Systems II: Express Briefs 66, no. 6 (June 2019): 948–52. http://dx.doi.org/10.1109/tcsii.2018.2870840.
15
Nuwanpriya, Asanka, Siu-Wai Ho, and Chung Shue Chen. "Indoor MIMO Visible Light Communications: Novel Angle Diversity Receivers for Mobile Users." IEEE Journal on Selected Areas in Communications 33, no. 9 (September 2015): 1780–92. http://dx.doi.org/10.1109/jsac.2015.2432514.
16
Mourier, Johann, Nathan Charles Bass, Tristan L. Guttridge, Joanna Day, and Culum Brown. "Does detection range matter for inferring social networks in a benthic shark using acoustic telemetry?" Royal Society Open Science 4, no. 9 (September 2017): 170485. http://dx.doi.org/10.1098/rsos.170485.
Abstract:
Accurately estimating contacts between animals can be critical in ecological studies such as examining social structure, predator–prey interactions or transmission of information and disease. While biotelemetry has been used successfully for such studies in terrestrial systems, it is still under development in the aquatic environment. Acoustic telemetry represents an attractive tool to investigate spatio-temporal behaviour of marine fish and has recently been suggested for monitoring underwater animal interactions. To evaluate the effectiveness of acoustic telemetry in recording interindividual contacts, we compared co-occurrence matrices deduced from three types of acoustic receivers varying in detection range in a benthic shark species. Our results demonstrate that (i) associations produced by acoustic receivers with a large detection range (i.e. Vemco VR2W) were significantly different from those produced by receivers with smaller ranges (i.e. Sonotronics miniSUR receivers and proximity loggers) and (ii) the position of individuals within their network, or centrality, also differed. These findings suggest that acoustic receivers with a large detection range may not be the best option to represent true social networks in the case of a benthic marine animal. While acoustic receivers are increasingly used by marine ecologists, we recommend users first evaluate the influence of detection range to depict accurate individual interactions before using these receivers for social or predator–prey studies. We also advocate for combining multiple receiver types depending on the ecological question being asked and the development of multi-sensor tags or testing of new automated proximity loggers, such as the Encounternet system, to improve the precision and accuracy of social and predator–prey interaction studies.
17
Lee, Chia-Wen, Tzu-Chun Huang, Wei-Shiang Lai, and Ching Li. "Sustainability of Health and Fitness Information Platform Ecosystem." Sustainability 13, no. 10 (May 17, 2021): 5560. http://dx.doi.org/10.3390/su13105560.
Abstract:
The roles of content producers, information receivers, and platform operators affect the stability of the governance of informational platforms. The purpose of this study was to identify and explore the sustainable factors of a platform ecosystem for health and fitness apps across Mainland China and Taiwan by interviewing producers, receivers, and operators. An advanced analytic hierarchy process (AHP) method was applied to derive expert perspectives from apps users and operators, live streamers, key opinion leaders, scholars, and officers across Mainland China and Taiwan via four dimensions and fourteen sub-dimensions of the initial health and fitness apps. The results revealed that the weights of the dimensions of health and fitness apps were sorted by content categories, content updates, user reviews, and platform terms; furthermore, the weights of the six highest sub-dimensions were the following: exercise, new feature, functionality, correctness, monitoring, and privacy. Content producers in Taiwan cared the most about the content category, whereas content producers in Mainland China cared the most about user reviews. Information receivers in Taiwan graded the content category the highest, whereas information receivers in Mainland China rated content updates the highest. Platform operators in Taiwan paid most attention to the platform terms, whereas the platform operators in Mainland China were most concerned with the content category. This comparative study can contribute to assisting the health and fitness industry across Mainland China and Taiwan area to provide an overall strategic operative process by identifying the effectiveness of the procedures, estimative processes, and cost reduction to enhance the competitiveness and further improve users’ experiences and satisfaction for the sustainability of health and fitness information platform Ecosystem.
18
Angelosante, Daniele, Ezio Biglieri, and Marco Lops. "Low-complexity receivers for multiuser detection with an unknown number of active users." Signal Processing 90, no. 5 (May 2010): 1486–95. http://dx.doi.org/10.1016/j.sigpro.2009.10.019.
19
Gao, Ronghai, Jiwen Zeng, and Lunzhi Deng. "An efficient certificateless multi-receiver threshold decryption scheme." RAIRO - Theoretical Informatics and Applications 53, no. 1-2 (January 2019): 67–84. http://dx.doi.org/10.1051/ita/2019001.
Abstract:
Threshold decryption allows only quorum cooperate users to decrypt ciphertext encrypted under a public key. However, such threshold decryption scheme cannot be applied well in this situation where all users have their public and private key pairs, but do not share any private keys corresponding to the public keys, such as mobile network featured with dynamic character. The direct way to achieve threshold decryption in this case is to divide the message into several pieces and then encrypt these pieces with the public keys of different users. However, this is very inefficient. Multireceiver threshold decryption scheme that could be applied efficiently in the above situation. Recently, some certificateless (ID-based) multireceiver threshold decryption (signcryption) schemes are introduced. But the bilinear pairings are used in most of the existing schemes. In this paper, we propose an efficient certificateless threshold decryption scheme using elliptic curve cryptography (ECC) without bilinear pairing. Performance analysis shows that the proposed scheme has lower computation cost than existing some threshold decryption schemes in both encryption and decryption process. Security analysis shows that our scheme is IND-CCA secure, and no one outside of selected receivers can disclose receivers identities, against the adversaries defined in CL-PKC system under the random oracle model.
20
Zuberi, Habib H., Songzuo Liu, and Mohammad Bilal. "Downlink Non-Orthogonal multiple access underwater acoustic communication receiver design Deep neural network." Journal of the Acoustical Society of America 154, no. 4_supplement (October 1, 2023): A250. http://dx.doi.org/10.1121/10.0023449.
Abstract:
Downlink non-orthogonal multiple access (NOMA) is necessary to handle the underwater acoustic channel's limitations on bandwidth. NOMA downlink underwater acoustic (UWA) communication transmits data symbols from a source station to many users. Superimposed coding with variable power levels allows successive interference cancelation (SIC) receivers to decode data. However, SIC receivers require knowledge of channel conditions and channel state information (CSI). This is difficult to acquire, particularly in UWA communication. To address this problem, this paper proposes downlink underwater acoustic using 1D Convolution neural network (CNN). Two users with different power levels and distances from the transmitter employ BPSK modulation to support multiuser communication. Users far from the base station receive the most power. The base station uses superimposed coding. BELLHOP algorithm generates the training dataset with user depth modifications. For training the model, a composite signal passes through the samples of the UWA channel and is fed to the model along with labels. DNN receiver learns the characteristic of the UWA channel and does not depend on CSI. The testing CIR is used to evaluate the trained model. The results are compared to the traditional SIC receiver. The DNN-based DL NOMA underwater acoustic receiver outperformed the SIC receiver in simulations.
21
Li, Xie, and Ren Yanli. "Efficient Anonymous Identity-Based Broadcast Encryption without Random Oracles." International Journal of Digital Crime and Forensics 6, no. 2 (April 2014): 40–51. http://dx.doi.org/10.4018/ijdcf.2014040103.
Abstract:
Broadcast encryption provides a method of secure multi-receiver communications, where a broadcaster can encrypt a message for a set S of users who are listening to a broadcast channel. Most identity-based broadcast encryption (IBBE) schemes are not anonymous, which means the attacker can obtain the identities of all receivers from the ciphertext. In this paper, the authors propose an efficient anonymous IBBE scheme in bilinear groups of prime order, where any attacker cannot get the identities of the receivers from the ciphertext. The scheme has constant size ciphertext and achieves adaptive security based on the asymmetric decisional bilinear Diffie-Hellman Exponent (DBDHE) assumption without random oracles. The proposed scheme improves efficiency and security of anonymous IBBE schemes simultaneously.
22
Heupel, M. R., J. M. Semmens, and A. J. Hobday. "Automated acoustic tracking of aquatic animals: scales, design and deployment of listening station arrays." Marine and Freshwater Research 57, no. 1 (2006): 1. http://dx.doi.org/10.1071/mf05091.
Abstract:
The recent introduction of low-cost, moored data-logging acoustic receivers has provided opportunities for tracking marine organisms over small (hundreds of metres) and large scales (hundreds of kilometres). Acoustic receivers have been deployed in many different environments to examine specific hypotheses regarding the movement of aquatic species. This technology provides many advantages for studying aquatic animal movement patterns, but also has limitations and provides unique difficulties for users. Study design, applications, advantages and limitations are discussed with examples from past and current studies. Data management and analysis techniques are in their infancy and few standardised techniques exist. Complications with data management and potential data analysis techniques are discussed. Examples from the literature are utilised wherever possible to provide useful references.
23
Gučević, Jelena, Siniša Delčev, and Olivera Vasović Šimšić. "Practical Limitations of Using the Tilt Compensation Function of the GNSS/IMU Receiver." Remote Sensing 16, no. 8 (April 10, 2024): 1327. http://dx.doi.org/10.3390/rs16081327.
Abstract:
The research in this paper is related to the accuracy of the tilt compensation function of the GNSS/IMU receivers, which were examined in an open sky environment. The purpose of the paper is to point out to geodesists the conditions and limitations of using GNSS/IMU technology in precise measurements to not jeopardize the coordinate’s accuracy. The environment in which the measurement is made affects the quality of the GNSS signal and can limit the visibility of the satellite, leading to larger errors in the measurement. In this experiment, the current performance of the GNSS/IMU receivers was checked. Seven GNSS/IMU receivers were used for the realization of the experiment. For six receivers the compensation angle was α = 30°, while for one receiver, the compensation angle was α = 45°. The standard uncertainty of GNSS coordinates of the antenna phase center has values less than 9 mm. The standard uncertainty of the IMU component has values less than 31 mm. The measurement uncertainty of the position of the used GNSS receivers is in the range of 18.1 mm to 31.7 mm. The limit values for the differences along the coordinate axes x and y were determined, and their values are from 26 mm to 44 mm. In the conducted experiment, it was confirmed that three GNSS/IMU receivers have a “Satisfactory” result. The results show that GNSS/IMU measurements with a slope greater than 30° significantly affect the accuracy and reliability of GNSS/IMU technology. A slope greater than 45° has a deviation along the coordinate axes of 121.3 mm. The conducted research is particularly important for geodetic works that require high positioning performance. The testing method of the GNSS/IMU receiver presented in this paper can help its users to make correct conclusions regarding the coordinate accuracy of the measured point of interest.
24
Li, Yue, Xuejun Sha, Liang Ye, and Xiaojie Fang. "Guard Band-Based Resource Sharing for Device-to-Device Communications Underlying Cellular Network." Mathematical Problems in Engineering 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/9547560.
Abstract:
The performance of device-to-device (D2D) communication in a cellular network depends on the resource sharing between D2D links and cellular users. Existing researches on resource sharing mainly focus on power control between the D2D users and cellular users that operate in the same frequency band. However, the D2D outage probability performance is hampered by the cellular interference to D2D links. Therefore, the D2D users may not achieve satisfactory SINR performance when D2D users and cellular users are geographically located in a small area; as a result, the outage probability performance would be significantly degraded. In this paper, we provide a novel resource sharing strategy to mitigate the interference from cellular users to D2D receivers by utilizing the low energy characteristics of signals in the guard band and analyze the D2D outage probability performance mathematically. Both the mathematical analysis and numerical results show that the proposed resource sharing strategy provides 1.2 dB SNR gain in D2D outage probability performance while guaranteeing the cellular throughputs.
25
Wang, Qixing, Ting Zhou, Hanzhong Zhang, Honglin Hu, Edison Pignaton de Freitas, and Songlin Feng. "Deep Learning-Based Detection Algorithm for the Multi-User MIMO-NOMA System." Electronics 13, no. 2 (January 5, 2024): 255. http://dx.doi.org/10.3390/electronics13020255.
Abstract:
Recently, non-orthogonal multiple access (NOMA) has become prevalent in 5G communication. However, the traditional successive interference cancellation (SIC) receivers for NOMA still encounter challenges. The near-far effect between the users and the base stations (BS) results in a higher bit error rate (BER) for the SIC receiver. Additionally, the linear detection algorithm used in each SIC stage fails to eliminate the interference and is susceptible to error propagation. Consequently, designing a high-performance NOMA system receiver is a crucial challenge in NOMA research and particularly in signal detection. Focusing on the signal detection of the receiver in the NOMA system, the main work is as follows. (1) This thesis leverages the strengths of deep neural networks (DNNs) for nonlinear detection and incorporates the low computational complexity of the successive interference cancellation (SIC) structure. The proposed solution introduces a feedback deep neural network (FDNN) receiver to replace the SIC in signal detection. By employing a deep neural network for nonlinear detection at each stage, the receiver mitigates error propagation, lowers the BER in NOMA systems, and enhances resistance against inter-user interference (IUI). (2) We describe its algorithm flow and provide simulation results comparing FDNN and SIC receivers under MIMO-NOMA scenarios. The simulations clearly demonstrate that FDNN receivers outperform SIC receivers in terms of BER for MIMO-NOMA systems.
26
Aquino, Marcio, Terry Moore, Alan Dodson, Sam Waugh, Jock Souter, and Fabiano S. Rodrigues. "Implications of Ionospheric Scintillation for GNSS Users in Northern Europe." Journal of Navigation 58, no. 2 (April 18, 2005): 241–56. http://dx.doi.org/10.1017/s0373463305003218.
Abstract:
Extensive ionospheric scintillation and Total Electron Content (TEC) data were collected by the Institute of Engineering Surveying and Space Geodesy (IESSG) in Northern Europe during years of great impact of the solar maximum on GNSS users (2001–2003). The ionospheric TEC is responsible for range errors due to its time delay effect on transionospheric signals. Electron density irregularities in the ionosphere, occurring frequently during these years, are responsible for (phase and amplitude) fluctuations on GNSS signals, known as ionospheric scintillation. Since June 2001 four GPS Ionospheric Scintillation and TEC Monitor receivers (the NovAtel/AJ Systems GSV4004) have been deployed at stations in the UK and Norway, forming a Northern European network, covering geographic latitudes from 53° to 70° N approximately. These receivers compute and record GPS phase and amplitude scintillation parameters, as well as TEC and TEC variations. The project involved setting up the network and developing automated archiving and data analysis strategies, aiming to study the impact of scintillation on DGPS and EGNOS users, and on different GPS receiver technologies. In order to characterise scintillation and TEC variations over Northern Europe, as well as investigate correlation with geomagnetic activity, long-term statistical analyses were also produced. This paper summarises our findings, providing an overview of the potential implications of ionospheric scintillation for the GNSS user in Northern Europe.
27
Weissar, Petr, Jiri Pinker, Miloslava Hrichova, and Jaroslav Firt. "New Method of Program Selection in Digital TV Receivers and its Evaluation by Users." Journal of Advanced Computational Intelligence and Intelligent Informatics 8, no. 5 (September 20, 2004): 530–34. http://dx.doi.org/10.20965/jaciii.2004.p0530.
Abstract:
A novel type of a user-friendly "man-to-TV set" interface has been designed for the new generation of digital TV sets with many hundreds of channels. It consists of an optimised remote-control device and a system of menus appearing on the TV screen. Response of potential users has been tested on the groups of students of different age and education, including seniors. Positive results have shown that the new TV control system can be used in practice.
28
Mercurio, M., and R. Reyes. "THE APPLICABILITY OF LOW-COST MULTI-FREQUENCY MULTI-GNSS RECEIVERS FOR GEODETIC CONTROL SURVEYING." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVIII-4/W8-2023 (April 25, 2024): 371–77. http://dx.doi.org/10.5194/isprs-archives-xlviii-4-w8-2023-371-2024.
Abstract:
Abstract. In geodetic surveys, survey-grade receivers are conventionally used due to their accuracy. However, expensive survey-grade receivers deter users from performing geodetic surveys utilizing the technology. Considerably, multi-system and multi-frequency low-cost GNSS receivers are available today, which can already provide good positioning accuracy output. This paper evaluates the performance of low-cost GNSS receivers in single-point positioning, relative positioning, and network solutions compared to survey-grade GNSS receivers. The study used a survey-grade antenna to test the u-blox C099-F9P evaluation kit equipped with the ZED-F9P module, a low-cost GNSS receiver. Simultaneously, the survey-grade GNSS receiver utilizes the same antenna using a GPS splitter to ensure simultaneous observation. Based on the results, the low-cost GNSS receiver is comparable to the survey-grade GNSS receiver for single and relative positioning. For single-point positioning, the low-cost GNSS receiver achieved 1- and 1.5-meter accuracy in horizontal and vertical components at a 95% confidence level, respectively. In relative positioning, it achieved an accuracy of 1 millimeter on average at a 95% confidence level. The network solution utilizes four (4) Active Geodetic Stations of the National Mapping and Resource Information Authority within the National Capital Region, used as reference stations. The low-cost GNSS receiver achieved an average accuracy of 8 millimeters. In summary, the ublox C099-F9P low-cost GNSS receiver achieved better than 1:100,000 or first-order survey accuracy stipulated in DAO 2007-29 surveying standards. Results show that the u-blox C099-F9P is possible for geodetic and other land surveying applications, even for high-accuracy requirements surveys.
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Wang, Desheng, Haizhen Liu, Xiaoqiang Ma, Jun Wang, Yanrong Peng, and Yanyan Wu. "Energy Harvesting for Internet of Things with Heterogeneous Users." Wireless Communications and Mobile Computing 2017 (2017): 1–15. http://dx.doi.org/10.1155/2017/1858532.
Abstract:
We study the energy harvesting problem in the Internet of Things with heterogeneous users, where there are three types of single-antenna users: ID users that only receive information, EH users that can only receive energy, and ID/EH users that receive information and energy simultaneously from a multiantenna base station via power splitting. We aim to maximize the minimum signal-to-interference-plus-noise ratio (SINR) of the ID users and ID/EH users by jointly designing the power allocation at the transmitter and the power splitting strategy at the ID/EH receivers under the maximum transmit power and the minimum energy harvesting constraints. Specifically, we first apply the semidefinite relaxation (SDR), zero-forcing (ZF), and maximum ratio transmission (MRT) techniques to solve the nonconvex problems. We then apply the zero-forcing dirty paper coding (ZF-DPC) technique to eliminate the multiuser interference and derive the closed-form optimal solution. Numerical results show that ZF-DPC provides higher achievable minimum SINR than SDR and ZF in most cases.
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Barhorst, Jennifer Brannon, Alan Wilson, Graeme James McLean, and Joshua Brooks. "Service encounter microblog word of mouth and its impact on firm reputation." Journal of Services Marketing 34, no. 5 (May 29, 2020): 717–33. http://dx.doi.org/10.1108/jsm-07-2019-0263.
Abstract:
Purpose It has now become a normal part of the consumption journey for consumers to share their positive and negative service encounters with firms on microblogs such as Twitter. There is, however, a limited amount of research on service encounter microblog word of mouth (SEMWOM) and its impact on firm reputation from a receiver’s perspective. This study aims to understand the comparative effects of positive and negative valence SEMWOM on receivers’ perceptions of firms’ reputations and the factors that are particularly salient to receivers’ perceptions of firm reputation upon exposure to SEMWOM. Design/methodology/approach An experiment exposed 372 Twitter users to positive and negative valence SEMWOM. To determine whether changes in perception of firm reputation occurred on exposure to both positive and negative valence SEMWOM, participants’ perceptions of a range of US airlines were measured before and after exposure to the SEMWOM. To confirm the factors that influence the perception of reputation on such exposure, six structural equation models were created to determine the comparative effects of positive and negative valence SEMWOM among three electronic WOM media as follows: video, photo and text. Findings Both positive and negative valence SEMWOM affect receivers’ perceptions of airlines’ reputations on exposure. Furthermore, the factors that influence perceptions of reputation on exposure to SEMWOM vary depending on valence and type of media contained in a tweet. Originality/value Although consumers now routinely share their positive and negative service encounters with brands on microblogs, scant research has examined receivers of positive and negative valence SEMWOM, important actors in the microblog domain. This study addresses this research gap by empirically investigating the impact of both positive and negative valence SEMWOM on receivers’ perceptions of firm reputation upon exposure to it.
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Do, Dinh-Thuan, Minh-Sang Van Nguyen, Thi-Anh Hoang, and Byung Moo Lee. "Exploiting Joint Base Station Equipped Multiple Antenna and Full-Duplex D2D Users in Power Domain Division Based Multiple Access Networks." Sensors 19, no. 11 (May 30, 2019): 2475. http://dx.doi.org/10.3390/s19112475.
Abstract:
In this paper, we investigate power domain division-based multiple access (PDMA) to support the base stations (BS) equipped with multiple antennas to serve mobile users. Such a system deploys multiple input single output (MISO)-based wireless transmission and a full-duplex (FD) scheme. Furthermore, such MISO PDMA system consists of BS employing transmit antenna selection to reduce complexity in signal processing at the receivers. We distinguish two kinds of mobile users, device-to-device (D2D) users and traditional users. In such MISO PDMA, there exists a trade-off between outage performance of each PDMA user and power allocation factors. Since the implementation of the FD scheme at PDMA users, bandwidth efficiency will be enhanced despite the existence of self-interference related to such FD. In particular, exact expressions of outage probability are derived to exhibit system performance with respect to D2D users. Finally, valuable results from the simulated parameters together with the analytical results show that MISO PDMA can improve its performance by increasing the number of transmit antennas at the BS.
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Howe, Bruce M., and James H. Miller. "Acoustic Sensing for Ocean Research." Marine Technology Society Journal 38, no. 2 (June 1, 2004): 144–54. http://dx.doi.org/10.4031/002533204787522811.
Abstract:
Ocean observatories have the potential to examine the physical, chemical, biological, and geological parameters and processes of the ocean at time and space scales previously unexplored. Acoustics provides an efficient and cost-effective means by which these parameters and processes can be measured and information can be communicated. Integrated acoustics systems providing navigation and communications and conducting acoustic measurements in support of science applications are, in concept, analogous to the Global Positioning System, but rely on acoustics because the ocean is opaque to electromagnetic waves and transparent to sound. A series of nested systems is envisioned, from small- to regional- to basin-scale. A small number of acoustic sources sending coded, low power signals can service unlimited numbers of inexpensive receivers. Drifting and fixed receivers can be tracked accurately while collecting ocean circulation and heat content data (both point and integral data), as well as ambient sound data about wind, rain, marine mammals, seismic T-phases, and anthropogenic activity. The sources can also transmit control data from users to remote instruments, and if paired with receivers enable two-way acoustic communications links. Acoustic instrumentation that shares the acoustic spectrum completes the concept of integrated acoustics systems. The ocean observations presently in the planning and implementation stages will require these integrated acoustics systems.
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Tomaštík, Julián, and Tim Everett. "Static Positioning under Tree Canopy Using Low-Cost GNSS Receivers and Adapted RTKLIB Software." Sensors 23, no. 6 (March 15, 2023): 3136. http://dx.doi.org/10.3390/s23063136.
Abstract:
The decrease in costs and dimensions of GNSS receivers has enabled their adoption for a very wide range of users. Formerly mediocre positioning performance is benefiting from recent technology advances, namely the adoption of multi-constellation, multi-frequency receivers. In our study, we evaluate signal characteristics and horizontal accuracies achievable with two low-cost receivers—a Google Pixel 5 smartphone and a u-Blox ZED F9P standalone receiver. The considered conditions include open area with nearly optimal signal reception, but also locations with differing amounts of tree canopy. GNSS data were acquired using ten 20 min observations under leaf-on and leaf-off conditions. Post-processing in static mode was conducted using the Demo5 fork of the RTKLIB open source software, which is adapted for usage with lower quality measurement data. The F9P receiver provided consistent results with sub-decimeter median horizontal errors even under tree canopy. The errors for the Pixel 5 smartphone were under 0.5 m under open-sky conditions and around 1.5 m under vegetation canopy. The adaptation of the post-processing software to lower quality data was proven crucial, especially for the smartphone. In terms of signal quality (carrier-to-noise density, multipath), the standalone receiver provided significantly better data than the smartphone.
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H.Vincent Poor, Narayan B. Mandayam, Wade Trappe, and Andrey Garnaev. "A multi-link communication connectivity game under hostile interference." ITU Journal on Future and Evolving Technologies 2, no. 1 (April 12, 2021): 101–12. http://dx.doi.org/10.52953/swhp5412.
Abstract:
In this paper, we consider a communication connectivity problem involving a primary user (transmitter, for example, a Ground Control Station (GCS)) servicing a group of secondary users (receivers, for example, drones) under hostile interference. We formulate this multi-link communication connectivity problem, where the channels are affected by Rayleigh fading, as a zero-sum power resource allocation game between a transmitter and an adversary (jammer). The transmitter's objective is to maximize the probability of communication connectivity with all the receivers. It is proven that the problem has unique equilibrium in power allocation strategies, and the equilibrium is derived in closed form. Moreover, we reduce the problem of designing the equilibrium in power resource allocation strategies to the problem of finding a fixed point of a real-valued function. An algorithm based on the bisection method to find the fixed point (and so equilibrium strategies) is developed, and its convergence is proven.
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El-Rahman, Mahmoud Abd, and Ahmed El-Rabbany. "Performance Evaluation of USTEC Product for Single-Frequency Precise Point Positioning." GEOMATICA 67, no. 4 (December 2013): 253–57. http://dx.doi.org/10.5623/cig2013-051.
Abstract:
Geodetic-grade dual-frequency GPS receivers are typically used for precise point positioning (PPP). Unfortunately, these receiver systems are expensive and may not provide a cost-effective solution in many instances. The use of low-cost single-frequency GPS receivers, on the other hand, are limited by the effect of ionospheric delay. A number of mitigation techniques have been proposed to account for the effect of ionospheric delay for single-frequency GPS users. Unfortunately, however, those mitigation techniques are not suitable for PPP. More recently, the U.S. Total Electron Content (USTEC) product has been developed by the National Oceanic and Atmospheric Administration (NOAA), which describes the ionospheric total electron content in high resolution over most of North America. This paper investigates the performance of USTEC and studies its effect on single-frequency PPP solution. A performance comparison with two widely-used ionospheric mitigation models is also presented.
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Zhu, Hailing, and Khmaies Ouahada. "Investigating Random Linear Coding from a Pricing Perspective." Entropy 20, no. 8 (July 25, 2018): 548. http://dx.doi.org/10.3390/e20080548.
Abstract:
In this paper, we study the implications of using a form of network coding known as Random Linear Coding (RLC) for unicast communications from an economic perspective by investigating a simple scenario, in which several network nodes, the users, download files from the Internet via another network node, the sender, and the receivers as users pay a certain price to the sender for this service. The mean packet delay for a transmission scheme with RLC is analyzed and applied into an optimal pricing model to characterize the optimal admission rate, price and revenue. The simulation results show that RLC achieves better performance in terms of both mean packet delay and revenue compared to the basic retransmission scheme.
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Jongore, Magret, and Chipo Chirimuuta. "An Exploration of Social Media as Forms of Social Control and Political Othering." International Journal of E-Politics 10, no. 1 (January 2019): 35–48. http://dx.doi.org/10.4018/ijep.2019010103.
Abstract:
The twenty-first century problem is of “Othering.” In a world beset by challenges, global, national, and regional conflict wrapped within or organized around group-based difference. The concept of “Othering” is used for social media platforms as the cause of many, if not all of the stresses of globalization, and the “collision of cultures.” This article discusses the advantages and disadvantages of social media in the wake of political othering on the Zimbabwean political landscape. More so, political othering is viewed as exacerbated by the various manipulations of different social media platforms. The article uses critical discourse analysis to unravel the unequal power relations inherent in social media platforms as both users and receivers of the peddled messages. Much as public media platforms are known to propagate a certain kind of mediated reality aimed at agenda setting and ideological persuasion in the presumed receivers. Social media platforms are used to negatively propagate rivalry, especially among political opponents.
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Manglayev, Talgat, Refik Kizilirmak, and Nor Hamid. "GPU Accelerated PIC and SIC for OFDM-NOMA." Electronics 8, no. 3 (February 26, 2019): 257. http://dx.doi.org/10.3390/electronics8030257.
Abstract:
Non-orthogonal multiple access (NOMA) is a candidate multiple access scheme for the fifth-generation (5G) cellular networks. In NOMA systems, all users operate at the same frequency and time, which poses a challenge in the decoding process at the receiver side. In this work, the two most popular receiver structures, successive interference cancellation (SIC) and parallel interference cancellation (PIC) receivers, for NOMA reverse channel are implemented on a graphics processing unit (GPU) and compared. Orthogonal frequency division multiplexing (OFDM) is considered. The high computational complexity of interference cancellation receivers undermines the potential deployment of NOMA systems. GPU acceleration, however, challenges this weakness, and our numerical results show speedups of about from 75–220-times as compared to a multi-thread implementation on a central processing unit (CPU). SIC and PIC multi-thread execution time on different platforms reveals the potential of GPU in wireless communications. Furthermore, the successful decoding rates of the SIC and PIC are evaluated and compared in terms of bit error rate.
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Bui, Anh, and Kazushi Nishimoto. "A Dual-Role Collaborative Learning Support System for Simultaneous Speaking Acquisition in English and Japanese." International Journal of Knowledge and Systems Science 13, no. 1 (January 2022): 1–19. http://dx.doi.org/10.4018/ijkss.298709.
Abstract:
Learning a foreign language is becoming more vital in Japan as a result of globalization. It gives foreigners various reasons to study Japanese including working or living in Japan. They should exchange language and skills and generate opportunities for engagement. Assisting them in exchanging linguistic skills and knowledge is critical. This study first proposes a theoretical model of dual-role collaborative learning to improve second language learners' speaking skills. Learners will participate as facilitators in their native language and receivers in their second language. Some supporting features must be given, followed by a Computer-supported Collaborative Learning (CSCL) named BiTak which is a video chat system that allows strict turn-taking dual-lingual conversation. The learner’s progress is positively evaluated by language teachers using a Rubric scoring framework. Based on the experiment results, it was concluded that BiTak has turned users' perspectives of video chat programs into collaborative learning platforms, allowing them to act as facilitators and receivers.
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Swaszek, Peter F., Richard J. Hartnett, and Kelly C. Seals. "Lower Bounds on DOP." Journal of Navigation 70, no. 5 (June 22, 2017): 1041–61. http://dx.doi.org/10.1017/s0373463317000248.
Abstract:
Code phase Global Navigation Satellite System (GNSS) positioning performance is often described by the Geometric or Position Dilution of Precision (GDOP or PDOP), functions of the number of satellites employed in the solution and their geometry. This paper develops lower bounds to both metrics solely as functions of the number of satellites, effectively removing the added complexity caused by their locations in the sky, to allow users to assess how well their receivers are performing with respect to the best possible performance. Such bounds will be useful as receivers sub-select from the plethora of satellites available with multiple GNSS constellations. The bounds are initially developed for one constellation assuming that the satellites are at or above the horizon. Satellite constellations that essentially achieve the bounds are discussed, again with value toward the problem of satellite selection. The bounds are then extended to a non-zero mask angle and to multiple constellations.
41
Zhao, Hongmei, Qian Wang, and Kunfeng Shi. "Analysis on Human Blockage Path Loss and Shadow Fading in Millimeter-Wave Band." International Journal of Antennas and Propagation 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/7540202.
Abstract:
Millimeter-wave (Mm-w) is the trend of communication development in the future; users who carry mobile communication equipment could be blocked by others in a crowded population environment. Based on Shooting and Bouncing Ray (SBR) method and setting up different orientation receivers (RX), population density, and people fabric property at 28 GHz and 38 GHz, simulating experimental scene similar to station square by Wireless Insite software, we use least square method to do linear-regression analysis for path loss and build path loss model. The result shows that the path loss index has a certain change in the different frequency, orientation receivers, population density, and people fabric. The path loss index of RouteC1 and RouteA2 has an obvious change in the central transmitter (TX). Each route shadow fading obeys Gaussian distribution whose mean is 0. This paper’s result has a theoretical guiding for designing the communication system in a crowded population environment.
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Danskin, Scott D., Pete Bettinger, Thomas R. Jordan, and Chris Cieszewski. "A Comparison of GPS Performance in a Southern Hardwood Forest: Exploring Low-Cost Solutions for Forestry Applications." Southern Journal of Applied Forestry 33, no. 1 (February 1, 2009): 9–16. http://dx.doi.org/10.1093/sjaf/33.1.9.
Abstract:
Abstract The global positioning system (GPS) exhibits much potential for forestry applications, where traditional methods of position determination still dominate. Recent advances in GPS technology may offer improved performance of GPS in forested conditions, and at a considerable cost advantage compared with previous GPS alternatives. We examined the use of several mapping- to recreation-grade GPS receivers across a topographic gradient and the influence of using the Wide Area Augmentation System (WAAS) to their performance under leaf-on and leaf-off conditions. Generally, the mapping-grade receiver with postprocessed differential correction offered the highest position accuracies, which improved root mean squared error (RMSE95) from 3.64 to 5.32 m across leaf conditions, compared with recreation-grade receiver performance, which ranged in RMSE95 from 12.76 to 38.74 m under leaf-on conditions to 8.22 to 36.81 m under leaf-off conditions. Users of this information should keep in mind that RMSE95 equals actual RMSE × 1.7308. These results are consistent with the general thoughts that (a) mapping-grade receivers should provide higher horizontal position accuracy than consumer-grade receivers, (b) better horizontal position accuracy is obtained during leaf-off forest conditions (i.e., winter), (c) differential correction can improve horizontal position accuracy, and (d) WAAS, when available, can improve horizontal position accuracy. Results also indicate that slope position and the number of position fixes acquired may influence the performance of the GPS units.
43
Ma, Lihua. "The Role of Geostationary Earth Orbit Communication Satellites in Chinese Area Positioning System." Artificial Satellites 49, no. 3 (September 1, 2014): 151–59. http://dx.doi.org/10.2478/arsa-2014-0012.
Abstract:
Abstract The Chinese Area Positioning System (CAPS) is an area positioning system based on Geostationary Earth Orbit (GEO) communication satellites. Transponders on the satellites are used to retransmit navigation message and ranging signals generated from the ground master station, while users receive navigation signals to perform navigation and positioning tasks. Meanwhile, CAPS also develops bidirectional communication receivers using abundant transponders resources on Slightly Inclined Geostationary Orbit (SIGSO) communication satellites, thus realizing integration of navigation and communication in the coverage region.
44
Aldababsa, Mahmoud, Mesut Toka, Selahattin Gökçeli, Güneş Karabulut Kurt, and Oğuz Kucur. "A Tutorial on Nonorthogonal Multiple Access for 5G and Beyond." Wireless Communications and Mobile Computing 2018 (June 28, 2018): 1–24. http://dx.doi.org/10.1155/2018/9713450.
Abstract:
Today’s wireless networks allocate radio resources to users based on the orthogonal multiple access (OMA) principle. However, as the number of users increases, OMA based approaches may not meet the stringent emerging requirements including very high spectral efficiency, very low latency, and massive device connectivity. Nonorthogonal multiple access (NOMA) principle emerges as a solution to improve the spectral efficiency while allowing some degree of multiple access interference at receivers. In this tutorial style paper, we target providing a unified model for NOMA, including uplink and downlink transmissions, along with the extensions to multiple input multiple output and cooperative communication scenarios. Through numerical examples, we compare the performances of OMA and NOMA networks. Implementation aspects and open issues are also detailed.
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Hussein, Tabarek, and Ismael Sharhan Haburi. "BER Performance for Downlink NOMA." Wasit Journal of Engineering Sciences 10, no. 2 (August 1, 2022): 216–22. http://dx.doi.org/10.31185/ejuow.vol10.iss2.267.
Abstract:
Non-Orthogonal Multiple Access (NOMA) is a possible multiple access option for the coming generation of wireless communications that has a higher SE and takes advantage of network resource reuse. As a result, academic and industry researchers have recently looked into the error performance and capacity of NOMA schemes. Because of the non-orthogonal nature of NOMA technique, the main disadvantage is users’ interference, which is normally mitigated using interference cancellation techniques such as Successive Interference Cancellation (SIC) at the receivers. In this paper, we investigate the performance of NOMA and the power allocation strategy utilized on BER. We used BASK modulation with Rayleigh fading channel and AWGN channel. The numerical results show that NOMA works well in equal and different distances between users.
46
Pavlovčič-Prešeren, Polona, Franc Dimc, and Matej Bažec. "Exploiting the Sensitivity of Dual-Frequency Smartphones and GNSS Geodetic Receivers for Jammer Localization." Remote Sensing 15, no. 4 (February 20, 2023): 1157. http://dx.doi.org/10.3390/rs15041157.
Abstract:
Smartphones now dominate the Global Navigation Satellite System (GNSS) devices capable of collecting raw data. However, they also offer valuable research opportunities in intentional jamming, which has become a serious threat to the GNSS. Smartphones have the potential to locate jammers, but their robustness and sensitivity range need to be investigated first. In this study, the response of smartphones with dual-frequency, multi-constellation reception capability, namely, a Xiaomi Mi8, a Xiaomi 11T, a Samsung Galaxy S20, and a Huawei P40, to various single- and multi-frequency jammers is investigated. The two-day jamming experiments were conducted in a remote area with minimal impact on users, using these smartphones and two Leica GS18 and two Leica GS15 geodetic receivers, which were placed statically at the side of a road and in a line, approximately 10 m apart. A vehicle with jammers installed passed them several times at a constant speed. In one scenario, a person carrying the jammer was constantly tracked using a tacheometer to determine the exact distance to the receivers for each time stamp. The aim was, first, to determine the effects of the various jammers on the smartphones’ positioning capabilities and to compare their response in terms of the speed and quality of repositioning with professional geodetic receivers. Second, a method was developed to determine the position of the interference source by varying the signal loss threshold and the recovery time on the smartphone and the decaying carrier-to-noise ratio (CNR). The results indicate that GNSS observations from smartphones have an advantage over geodetic receivers in terms of localizing jammers because they do not lose the signal near the source of the jamming, but they are characterized by sudden drops in the CNR.
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Zuberi, Habib Hussain, Songzuo Liu, Muhammad Bilal, Ayman Alharbi, Amar Jaffar, Syed Agha Hussnain Mohsan, Abdulaziz Miyajan, and Mohsin Abrar Khan. "Deep-Neural-Network-Based Receiver Design for Downlink Non-Orthogonal Multiple-Access Underwater Acoustic Communication." Journal of Marine Science and Engineering 11, no. 11 (November 17, 2023): 2184. http://dx.doi.org/10.3390/jmse11112184.
Abstract:
The excavation of the ocean has led to the submersion of numerous autonomous vehicles and sensors. Hence, there is a growing need for multi-user underwater acoustic communication. On the other hand, due to the limited bandwidth of the underwater acoustic channel, downlink non-orthogonal multiple access (NOMA) is one of the fundamental pieces of technology for solving the problem of limited bandwidth, and it is expected to be beneficial for many modern wireless underwater acoustic applications. NOMA downlink underwater acoustic communication (UWA) is accomplished by broadcasting data symbols from a source station to several users, which uses superimposed coding with variable power levels to enable detection through successive interference cancellation (SIC) receivers. Nevertheless, comprehensive information of the channel condition and channel state information (CSI) are both essential for SIC receivers, but they can be difficult to obtain, particularly in an underwater environment. To address this critical issue, this research proposes downlink underwater acoustic communication using a deep neural network utilizing a 1D convolution neural network (CNN). Two cases are considered for the proposed system in the first case: in the first case, two users with different power levels and distances from the transmitter employ BPSK and QPSK modulations to support multi-user communication, while, in the second case, three users employ BPSK modulation. Users far from the base station receive the most power. The base station uses superimposed coding. The BELLHOP ray-tracing algorithm is utilized to generate the training dataset with user depth and range modifications. For training the model, a composite signal passes through the samples of the UWA channel and is fed to the model along with labels. The DNN receiver learns the characteristic of the UWA channel and does not depend on CSI. The testing CIR is used to evaluate the trained model. The results are compared to the traditional SIC receiver. The DNN-based DL NOMA underwater acoustic receiver outperformed the SIC receiver in terms of BER in simulation results for all the modulation orders.
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KOBAYASHI, YOSHIZUMI, HIROSHI ENOKI, QIANREN ZHANG, TADASHI OHTA, and NOBUYOSHI TERASHIMA. "ELICITATION OF NETWORK SERVICE SPECIFICATIONS FROM NATURAL LANGUAGE DESCRIPTIONS AT VARIOUS VIEWPOINTS." International Journal on Artificial Intelligence Tools 05, no. 03 (September 1996): 259–75. http://dx.doi.org/10.1142/s0218213096000171.
Abstract:
In order to respond to the increasingly diverse requirements for network services, it would be best if the specifications could be defined by the users who actually have those requirements. If the users themselves are to define the specifications, the best case would be to have them use the natural languages that they are familiar and comfortable with. Since network services become visible to the users via their terminals, when users write specifications for network services, the specifications may be defined in a form including specifications for the terminals in addition to network services. In this paper, we propose a method of extracting network service specifications from natural-language descriptions made from various points of view. First we will organize the concepts of network services on the basis of a model for network services. Next we will extract a number of viewpoints from the relationships between the network service providers and the receivers, i.e. the terminals and users, and clarify the relationships between those viewpoints and the network-service concepts. On the basis of this, we will propose a method for describing network service specifications in a natural language and for understanding them.
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Timoté, Cristhian Camilo, José Miguel Juan, Jaume Sanz, Guillermo González-Casado, Adrià Rovira-García, and Miquel Escudero. "Impact of medium-scale traveling ionospheric disturbances on network real-time kinematic services: CATNET study case." Journal of Space Weather and Space Climate 10 (2020): 29. http://dx.doi.org/10.1051/swsc/2020030.
Abstract:
Medium-scale traveling ionospheric disturbances (MSTIDs) are fluctuations in the plasma density that propagate through the upper layer of the atmosphere at velocities of approximately 100 m/s and periods reaching some tens of minutes. Due to their wavelengths, MSTIDs can degrade the performance of differential positioning techniques, such as real-time kinematics (RTK) or network-RTK (NRTK). This paper defines a novel methodology as a tool for relating the errors in NRTK positioning based on an MSTIDs indicator using the second difference in time of the slant total electron content (STEC). The proposed methodology performs integer ambiguity resolution (IAR) on the undifferenced measurements instead of using double-differenced carrier-phase measurements, as it is usual in RTK and NRTK. Statistical tests are applied to evaluate the degradation in the position errors caused by the impacts of MSTIDs on RTK and NRTK positioning over a data set spanning one year gathered from the CATNET network; a dual-frequency network of fixed permanent GNSS receivers located at the mid-latitudes of northeastern Spain. With the development of the proposed methodology for measuring the position degradation, another results of the present research are the establishment of thresholds for the proposed MSTIDs index, which can be used to monitor the positioning solution and to warn users when the measurements are affected by MSTIDs events, relating the position error to MSTIDs that affect not only the user receivers but also of the reference receivers within the network.
50
Jain, Anjali, and Agya Mishra. "Design of IoT based Real-Time Bus Tracking App using HF-RFID." International Journal of Recent Technology and Engineering 9, no. 6 (March 30, 2021): 71–75. http://dx.doi.org/10.35940/ijrte.f5365.039621.
Abstract:
Public Transportation is the major means of Bus among people. A recent survey by the National Sample Survey Organization says that about 62-66% of people use the bus as their mode of transport. Public Bus tracking system aims at providing the instant status of the bus to the users via an automated system. This paper describes a design of IoT enabled real time bus tracking system. In this work a bus tracking mobile phone app is developed, using that people can exactly locate the bus status and time to bus arrival at bus-stop. This work uses high frequency RFID tags at buses and RFID receivers at bus-stops and with NodeMCU real time RIFD tagging (bus running) information is collected and uploaded on cloud. Users can access the bus running and status from cloud on mobile app in real time.